The present invention concerns testing means for vehicle tires and anti-skid means, in which a vehicle tire to be tested is pressed against an outer circle or circumference of another tire while rotating the tires in opposite directions of rotation.
Several different apparatus are known in the prior art for testing vehicle tires and particularly anti-skid means placed in these tires. One such means of the state of the art is schematically illustrated in FIG. A1. The means of FIG. A1 comprises a stationary circle 2 provided with a wear surface, along the inner periphery of which a tire 1 to be tested is arranged to roll. In FIG. A2 another means of the state of the art is presented in which the tire 1 to be tested rolls along the outer periphery of a stationary circle 2. However, a significant drawback of this apparatus is that the tire 1 to be tested meets the circle 2 in an incorrect position, whereby it is not possible to simulate ordinary driving on a road with arrangements such as those described above.
In addition to the apparatus illustrated in FIGS. A1 and A2, an embodiment is known in which the circle 2 has been arranged to be rotatable, whereby the speed of rotation of the tire 1 to be tested is equally increased.
A third means of the state of the art is illustrated in FIG. A3, in which the tire 1 to be tested has been arranged to rotate along a circle 3 situated horizontally, this circle being either stationary or rotating. A drawback of this apparatus is, in turn, that the arrangement corresponds to continuous curve driving, whereby driving in the direct direction cannot be simulated with such means. In FIG. A4, another means of the state of art is presented in which, in a way, is a special application of FIG. A2. In the design of FIG. A4, the pair or counterpart for the tire 1 to be tested is a hard wheel, e.g. made of asphalt concrete, against which the tire 1 to be tested is pressed while rotating so that both the tire to be tested and the wheel 4 rotate. A poor feature of this design is the same as with the means of FIG. A2, i.e. that the tire 1 meets the wheel 4 in an incorrect position which is not equivalent to driving on a road.
Furthermore, additional means of the state of the art are presented in FIG. A5 comprising a belt roll system with an endless belt 7 carried around return rolls 5 and 6 and against which two tires 1a and 1b to be tested are urged on two opposite sides of the belt 7. In this arrangement, the tire 1a or 1b to be tested is arranged to meet the belt in a position equivalent to a position of driving on a road. A significant drawback of this apparatus, however, is that the design of the testing means is exceedingly complex and the belt 7 being used in the apparatus is of a special structure and is very expensive.